Sorry for the slightly off topic question but does the unit have a radio built in? Nothing mentioned on the spec sheets you've linked, just the presence of a radio antenna input in the photo... If yes, does it have a digital HD radio or is it just analogue?

 

The Joying units seem to mostly be based on the Android operating system, and come with a built-in AM/FM radio app that uses the onboard tuner.

 

As promised, the short movies of what’s going on:

 

It's hard to tell what connections you have made, and it looks like someone has chopped up your wiring harness.
Can you confirm that you have connected the "Amp Cont" wire from the back of the radio (should be orange, with an inline fuse) to the wire going to pin 5 of the gray connector?. Pin 5 has a red and blue wire going to it. I think that there is no wire going from that pin to the radio in the radio harness.

 

In both videos it doesn't sound like ground loop noise. When turning on consumers in the car (dome lights, headlights or ECU), the noise is gone, which is weird. It looks more like a problem with the unit, but check first if the head unit is properly grounded. Also, is the housing of the head unit connected to ground on the connector?

 

true, wiring harnass is chopped up. All the lose ends of cable you see are from the aftermarket navigation system that i totally removed thinking that might be the issue..

‘amp cont’ is connected to the red/blue cable as you mentioned...

 

when i turn on consumers, it looks like the amp is shut off, that’s why the sound is gone. When i play music and a consumer is turned the music also shuts off..

i’ve added a extra ground cable from de cable adapter to the same ground point the radio allready used, no difference.

i’ve grounded all 4 rca connectors to the radio housing ( red about on the internet), made no difference.

have not yet tried to ground the radio housing, will try that tomorrow and let you know.

could the dsp amp in this specific radio be the problem?
i don’t have another headunit at the moment to find out if the headunit itself is the problem..


thought it would be an easy job when i started, haha!

 

It looks like the wiring of the adapter is wrong or the head unit defective.

Check the wiring of the adapter first. If you post a picture of the pin connector on the Joying unit, I could tell you which pin goes where (in case you don't already know it).

 

Here's a picture of the pin connector from the joying radio;

 

That looks almost identical to the diagram for my unit, except for the 4G antenna connections.
I suspect that your problems may be with some of the butchered wiring, or possibly the amplifier. But try running a ground wire from the radio chassis to the metal dashboard frame just in case. Reliable ground wiring is important in a Discovery.